Apparatus and methods of visual demonstration of sound wave motion

ABSTRACT

An apparatus is provided for visually demonstrating sound wave motion in the form of a plurality of side-by-side reflective strips suspended vertically from one end, a source of moving fluid acting continuously on said strips and an indicating means normally reflected from the strips intermediate their ends.

I Umted States Patent 1 1 3,597,859

[72) Inventor Kenneth G. Salem References Cited 226 Belmon 81-. .l lin n. Pal 5?04 UNITED STATES PATENTS 1 I PP 353988 903.074 1 H1908 Forbes 35/19 I 1 PM 1.071.071 10/1926 Gritt 40/l06.54 I451 Palemed 1,976,093 9 1933 Raymond 40/l38 Continuation-impart ol apphcatmn Ser. No. I

75 74 No 14 19 3 Primary Exammer- Robert W. Mlchell Ass/slam Examiner-L. Anten Attorney-Buell, Blenko & Ziesenheim [S4] APPARATUS AND METHODS OF VISUAL BEE EJ P Q SOUND V MOTION ABSTRACT: An apparatus is provided for visually demonstrating sound wave motion in the form'of a plurality of side- [52] US. Cl 35/19 R b'y-side reflective strips suspended vertically from one end, a [51 Int. Cl ..G09b 23/06 source of moving fluid acting continuously on said strips and Field of Search 35/ 19; an indicating means normally reflected from the strips intermediate their ends.

Patented Aug. 10, 1971 INVENTOR Kenneth G. Salem APPARATUS AND METHODS OF VISUAL DEMONSTRATION OF SOUND WAVE MOTION This application is a continuation-in-part of my copending application Ser. No. 775,874 filed Nov. 14, 1968.

This invention relates to apparatus and methods of visual demonstration of sound wave motion and particularly to an apparatus and method of visual demonstration of sound waves based upon the effect of sound wave motion upon moving fluid such as air.

The motion of sound waves is not and has not been directly visible to the human eye. There are methods which have been used in the past by means of which sound motion is visibly demonstrated, some more complex than others. As an example, the oscilloscope visually records sound wave patterns on a screen as picked up and converted to electrical energy, Ripple tanks in which sound waves are simulated by wave motion in a body of water have been used as a demonstration means. Another system related to the oscilloscope technique is based upon picking up sounds in a microphone, converting the sound to electrical energy which is used to energize a light bulb, the variations in light level indicating the rise and fall of the sound wave pattern. Other less striking methods have also been used. No method has, however, been sufficiently inexpensive, uncomplicated and easily seen to meet with general I acceptance.

l have invented an apparatus and method for demonstrating sound waves which is inexpensive, easily used and highly effective for demonstrating sound wave patterns.

Preferably the apparatus comprises a plurality of side-byside reflective strips suspended vertically from one end, a source of moving fluid acting continuously on said strips and an indicating means normally reflected from the strips intermediate their ends. Preferably the strips are a highly reflective metal such as aluminum, suspended in a straight line side by side in a source of moving fluid such as air, preferably hot air from a heater or air from a ventilating fan. The indicating means is preferably simply a sheet of white paper upon which a light source is impinged and reflected against the strips.

In the foregoing general description of my invention I have set out certain objects, purposes and advantages of my invention.

Other objects, purposes and advantages of this invention will be apparent from a consideration of the following description and accompanying drawings in which;

FIG. I is an isometric view of an apparatus according to my invention.

FIG. 2 is a side elevation of the apparatus of FIG. 1.

Referring to the drawing, I have illustrated a base carrying a resistance heating unit II such as a Calrod unit having a connecting wire I2 by means ofwhich the unit is connected to a source of electrical power. A white sheet 13 is provided on a level adjacent the bottom of the strips 16. A vertical support standard 14 is fixed to the base adjacent the heat unit 11 with a suspension area 14a parallel to and equally spaced from heat unit. A sheet of aluminum foil 15 slit into a plurality of narrow strips I6 is suspended from arm 14a directly above the heat unit.

The operation of the device is as follows. Electrical current is introduced into heat unit 11 by means of wire 12. When heat unit 11 becomes hot, warm air rises, strikes the strips 16 causing them to move back and forth as shown in FIG. 2. The white sheet 13 appears as a reflection in the form of an essentially straight line midway between top and bottom of the strips. When a sound is made the motions of the currents of air are altered by the sound waves impinging on them thereby causing the motion of the strips to change with the sound. As a result the strips move independently of one another so that the white sheet 13 reflects to produce a wave motion I7 on their surface. This is a highly effective demonstration and particularly so if the strands are colored in a multiplicity of reflective colors running across the strips in lines parallel to the heat source.

My research indicates that the moving fluid may he turbulent as well as direct flowing to produce the desired result. As I have previously indicated it may be produced by heat waves, fans or any other source of moving fluid.

While I have illustrated and described a preferred practice of my invention, it will be understood that this invention may be otherwise embodied within the scope of the following claims.

Iclaim:

1. An apparatus for visually demonstrating sound wave motion comprisinga plurality of flexible side-by-side reflective strips suspended vertically from one end, a source of moving fluid sensitive to sound energy acting continuously on said strips, a source of light, and an indicating means reflected from the strips intermediate their ends defining at least one line across said reflective strips whose path varies in the presence of sound energy to define a path characteristic of the sound being demonstrated said indicating means including reflective means spaced from the reflective strips directing light from said light source onto the strip as said at lease one line said line having a maximum width less than the vertical length of said reflective strips.

v2. An apparatus as claimed in claim 1 wherein the reflective means is a white surface in a plane transverse to the plane of the reflective strips.

3. An apparatus as claimed in claim I wherein the source of moving fluid is a heating element producing heated air.

4. An apparatus as claimed in claim 1 wherein the reflective strips are aluminum foil. 

1. An apparatus for visually demonstrating sound wave motion comprising a plurality of flexible side-by-side reflective strips suspended vertically from one end, a source of moving fluid sensitive to sound energy acting continuously on said strips, a source of light, and an indicating means reflected from the strips intermediate their ends defining at least one line across said reflective strips whose path varies in the presence of sound energy to define a path characteristic of the sound being demonstrated said indicating means including reflective means spaced from the reflective strips directing light from said light source onto the strip as said at lease one line said line having a maximum width less than the vertical length of said reflective strips.
 2. An apparatus as claimed in claim 1 wherein the reflective means is a white surface in a plane transverse to the plane of the reflective strips.
 3. An apparatus as claimed in claim 1 wherein the source of moving fluid is a heating element producing heated air.
 4. An apparatus as claimed in claim 1 wherein the reflective strips are aluminum foil. 